P21AB
Reductant Level Sensor B Circuit High
P21AB is an OBD-II diagnostic trouble code meaning: Reductant Level Sensor B Circuit High. Common causes: reagent b level sensor malfunction, short circuit in the sensor circuit. Estimated repair cost: $33–89.
Symptoms
- Check Engine light comes on
- Reduced efficiency of the SCR system
- Possible engine power restrictions
- Low reagent level message may not display correctly
- Increased NOx emissions
Causes
- Reagent B level sensor malfunction
- Short circuit in the sensor circuit
- Broken or damaged wiring
- Problems with sensor connectors
- SCR control module malfunction
How to Fix
- Check the level and quality of the reagent (AdBlue)
- Visually inspect the sensor wiring and connectors
- Check the resistance and voltage in the sensor circuit
- Replace the reagent level sensor if necessary
- Test the operation of the SCR control module
Related codes
Error P21AB by Vehicle Brand
FAQ
What does the P21AB code mean?
P21AB is an OBD-II diagnostic trouble code that indicates: Reductant Level Sensor B Circuit High
What causes a P21AB error code?
The most common causes of P21AB include: Reagent B level sensor malfunction; Short circuit in the sensor circuit; Broken or damaged wiring; Problems with sensor connectors.
How do I fix a P21AB diagnostic trouble code?
To fix P21AB: Check the level and quality of the reagent (AdBlue). Visually inspect the sensor wiring and connectors. Check the resistance and voltage in the sensor circuit. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with P21AB?
Yes, but get it checked soon
How much does it cost to fix P21AB?
The estimated repair cost for P21AB is $33–89. Actual cost depends on your vehicle, location, and labor rates.
See also: Russian version · NationStat